Brian,
See blog discussion. NFS is just like iSCSI, only worse.
http://it.toolbox.com/blogs/database-soup/the-problem-with-iscsi-30602
If you *do* to this because management is more important than
performance, then budget for $2k or so worth of tuning & troubleshooting
services, or make sure that that's included by NetApp. You'll also need
NetApp's proprietary NFS tech to make it work at all.
Also note that lag time isn't such a problem for data warehousing as it
is for OLTP. And the bandwidth issues are solvable by using 10gE, but
that significantly increases the cost of your solution.
--Josh